[Piglit] [PATCH] gl-3.2/adj-prims: fix expected vertex order for triangle strips with adjacency

[Nicolai Hähnle]

From: Nicolai Hähnle <nicolai.haehnle at amd.com>

The first two vertices are swapped for triangle strips with adjacency; see
Table 10.1 of the OpenGL 4.5 (Compatibility Profile) spec.
---
 tests/spec/gl-3.2/adj-prims.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/tests/spec/gl-3.2/adj-prims.c b/tests/spec/gl-3.2/adj-prims.c
index 9d2f121..30c5f4b 100644
--- a/tests/spec/gl-3.2/adj-prims.c
+++ b/tests/spec/gl-3.2/adj-prims.c
@@ -166,23 +166,26 @@ provoking_vertex_index(GLenum prim_mode, GLenum pv_mode, unsigned prim_index)
 		if (pv_mode == GL_FIRST_VERTEX_CONVENTION)
 			return prim_index + 1;
 		else
 			return prim_index + 2;
 	case GL_TRIANGLES_ADJACENCY:
 		if (pv_mode == GL_FIRST_VERTEX_CONVENTION)
 			return prim_index * 6 + 0;
 		else
 			return prim_index * 6 + 4;
 	case GL_TRIANGLE_STRIP_ADJACENCY:
-		if (pv_mode == GL_FIRST_VERTEX_CONVENTION)
-			return prim_index * 2;
-		else
+		if (pv_mode == GL_FIRST_VERTEX_CONVENTION) {
+			if (prim_index & 1)
+				return prim_index * 2 + 2;
+			else
+				return prim_index * 2;
+		} else
 			return prim_index * 2 + 4;
 	default:
 		assert(!"Unexpected prim_mode");
 		return 0;
 	}
 }
 
 
 /**
  * Given a primitive type and a primitive (line/triangle) index, return
@@ -205,22 +208,27 @@ compute_probe_location(GLenum prim_mode, unsigned prim_index,
 		i0 = prim_index + 1;
 		i1 = prim_index + 2;
 		break;
 	case GL_TRIANGLES_ADJACENCY:
 		i0 = prim_index * 6 + 0;
 		i1 = prim_index * 6 + 2;
 		if (polygon_mode != GL_LINE)
 			i2 = prim_index * 6 + 4;
 		break;
 	case GL_TRIANGLE_STRIP_ADJACENCY:
-		i0 = prim_index * 2;
-		i1 = prim_index * 2 + 2;
+		if (prim_index & 1) {
+			i0 = prim_index * 2;
+			i1 = prim_index * 2 + 2;
+		} else {
+			i0 = prim_index * 2 + 2;
+			i1 = prim_index * 2;
+		}
 		if (polygon_mode != GL_LINE)
 			i2 = prim_index * 2 + 4;
 		break;
 	default:
 		assert(!"Unexpected prim_mode");
 		*x = *y = 0;
 		return;
 	}
 
 	/* average of 2 or 3 points */
-- 
2.7.4